net/mlx5e: Add TC offloads matching on IPv6 encapsulation headers

Enhance the parsing of offloaded TC rules to set HW matching on outer
IPv6 encapsulation headers. This effectively adds support for TC tunnel
key release action (decapsulation) of SRIOV offloads over IPv6 tunnels.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>